【转帖】query color inde
 

query: color index
query: color index
hi,
the documentation of odcmcolor::setcolorindex() says that indices 8-255 are defined by display device. my question is:
are these defaults set by autocad? (and if so do they change between autocad versions?)
or can we modify them? (i couln't find a method to do so in the odcmcolor class hierarchy.)
basically we were calculating the color index based on the hsv color model. this was when we were using odt. now with true color support, we still want to give the user the option of saving as indexed color. but apparently the color output produced by setting the same index renders differently (in some cases) from the old, when the new code runs with dd. has the interpretation of indices changed from odt to dd?
thanks.
autocad uses 2 different palettes for different backgrounds. (they may slightly differ between ac versions). dd code uses contains 2 palettes too (they are defined in acadpalettes.h) one of them is used to get aci from rgb while file saving.
as for display devices the palette used can be set by
virtual void odgsdevice::setlogicalpalette(
const odcolorref* logicalpalette,
int numcolors) = 0;
to produce gray scale printing for example.
if entity color is specified by index device will receive index and use a value from palette. if color is specified by rgb, device will receive rgb value.
sergey slezkin